S312 TUCANO T MK1 N206PZ accident near Maricopa, California

Probable cause

The pilot's failure to maintain clearance from terrain during low-level airwork, which resulted in uncontrolled collision with terrain. Contributing to the accident was the pilot's impairment from the combined effects of butalbital and codeine.

NTSB analysis

The private pilot was performing airwork and was in contact with an air traffic controller. The pilot informed the controller that he would be performing airwork between 2,500 and 10,000 ft mean sea level (msl). The controller explained that he would probably lose radio contact and would not be able to provide flight following below 7,000 ft msl. About 1 hour later, the pilot advised the controller that he would be descending, then would climb to 9,000 ft msl and return to the airport, and the controller acknowledged. Subsequently, the controller made several attempts to contact the pilot, but no further response was received from him. Shortly thereafter, an airplane flying in the area of the accident site reported to air traffic control that a small fire was located in a river bed. Local authorities responded to the fire and confirmed that it was the accident site.

A review of Federal Aviation Administration radar data showed the airplane performing multiple turns and rapidly changing altitude and airspeed while performing the airwork. At one point, the airplane descended to less than 100 ft above a mountain ridgeline. The last radar targets showed the airplane heading eastbound about 1,600 ft agl while approaching the area of the accident site. Two witnesses located near the accident site stated that, as the airplane flew overhead, they noted no engine anomalies.

Postaccident examination of the wreckage did not reveal any preimpact malfunctions that would have precluded normal operation. Wreckage and impact signatures were consistent with a high-energy high-angle impact with terrain. It is likely that as the pilot continued to perform low level airwork, he did not properly gauge the airplane's distance from terrain and failed to control the airplane in time to avoid impacting terrain.

The pilot's high cholesterol and the medications he was using to treat it likely did not cause any acute symptoms. Limited samples were available for toxicology testing; therefore, it could not be determined whether the ethanol detected in the pilot's muscle tissue was due to ingestion or postmortem production nor whether impairment due to ethanol contributed to the accident. The testing also detected butalbital and codeine, both of which are impairing. The butalbital was within the therapeutic level, indicating that he was likely impaired by it. The presence of both codeine and butalbital indicates that the pilot had likely recently used a combination product that contained at least these two medications. Therefore, it is likely that the pilot's mental and/or physical abilities required for the duration of the high workload flight performance was impaired by the combined effects of butalbital and codeine and that this impairment contributed to the accident.

Text from the NTSB. Open the NTSB docket for WPR15FA195 for the full record.